Sea Calendar, Year 1516.
Four years before luffy would set sail from East Blue to flip the world upside down.
In the vast expanse of the South Blue lies an island known as Twin Island. The name is literal; a massive freshwater river carves through the center of the landmass like a jagged scar, splitting the island into distinct northern and southern halves. It is a quiet, unassuming place, forgotten by the World Government and ignored by the larger warring factions of the sea. With a population of fewer than two thousand people living in a single, sleepy coastal town, it sits precariously on the edge of the South Blue and the terrifying stillness of the Calm Belt.
The sky today was a piercing, crystalline blue. A soft sea breeze, tinged with the sharp scent of salt and spray, rolled over the cliffs and deep into the island's rugged interior.
Deep within the northern mountain range, where the ridges were steep and the air was thin, a rhythmic, earth-shaking sound echoed through a secluded valley.
BOOM! BOOM! BOOM!
The source of the commotion was a young man. He stood nearly 1.9 meters tall, with a frame that was both lean and densely packed with functional, ropey muscle. His hair, a striking shade of silver, caught the sunlight as he moved with a fluid, terrifying precision. Despite his rugged appearance, his features were handsome, though currently set in a mask of grim, absolute focus.
In his hands was a long sword, its steel shimmering with every arc. He wasn't practicing forms against the air; he was relentlessly hacking at the literal mountainside. The cliff face before him was a chaotic tapestry of deep, jagged gouges. With every strike, shards of granite exploded outward, tumbling down into the valley floor.
"9,990... 9,991... 9,992..."
His voice was a low, steady growl. Sweat poured from his brow, matting his silver hair and soaking his training clothes until they clung to his skin like a second layer of armor. His muscles burned, screaming for a reprieve, but his grip on the hilt never wavered. The numbers climbed, fueled by a willpower that seemed to defy physical limits.
When he finally barked out the number "10,000," his entire aura shifted. He didn't just swing; he pivoted his entire weight, his blade whistling through the air in a perfect, horizontal arc.
A brilliant, translucent arc of compressed air, a Flying Slash tore through the void. It hummed with a sharp, high-pitched frequency as it collided with a massive boulder across the valley.
CRACK!
The rock, the size of a small carriage, split in two as cleanly as if it were made of warm butter.
"Wahahaha! I finally did it! A true Flying Slash!"
The young man collapsed onto the grassy floor of the valley, chest heaving as he gasped for air. He threw his head back, laughing toward the sky with a wild, arrogant glint in his eyes. "Being a Swordmaster isn't so tough after all!"
In this world, the Flying Slash was the hallmark of a true warrior of the blade. It was a technique that allowed a swordsman to project their intent and physical force through the air, turning a melee weapon into a long-range instrument of destruction. For most, it took decades of meditation and combat to achieve. For him, it was a milestone of pure, unadulterated "grinding."
The young man wasn't originally from these seas. In another life, on a world called Earth, he had been known as Jack, a twenty-three-year-old graduate working a soul-crushing job in e-commerce. He had spent his nights staring at spreadsheets and his days surviving on caffeine and overtime. His life had ended abruptly at 10:00 PM on a rainy Tuesday, when a wayward truck had sent him and his electric scooter into the afterlife.
When he woke up, he was no longer Jack the office worker. His soul had fused with that of a dying twelve-year-old boy named Cedric Reg.
The original Cedric was the son of a minor noble from the Ols Kingdom. In the year 1510, while the family was fleeing toward the Bliss Kingdom, their vessel was intercepted by pirates. His parents had been slaughtered before his eyes. It was only through his father's final act of desperation, shoving him into a wooden barrel that Cedric had survived. He had drifted for days across the South Blue until he washed up on the shores of Twin Island, his life force nearly extinguished.
That was the moment Jack's soul took over.
Initially, Jack had been terrified. Earth was stressful, sure, but you didn't usually have to worry about a three-story-tall sea monster eating your house. The One Piece world was a supernatural playground of chaos. Pirates were as common as seagulls, and the Celestial Dragons sat atop the world, treating human lives like disposable toys.
Looking at his frail, malnourished body six years ago, Jack knew he had only one choice: get strong or get buried.
Fortunately, the transmigration hadn't just given him a new life; it had granted him a "Golden Finger", a unique talent he called "Heaven Rewards the Diligent."
The logic was simple: in this world, some people were born with god-like Haki or overpowered Devil Fruits. Jack didn't have those, but he had a guarantee. As long as he put in the work, he would receive the rewards. There were no plateaus, no wasted efforts, and no limits to his growth. If he swung a sword ten thousand times, his proficiency must increase. If he pushed his muscles to the point of failure, they must come back stronger.
In six years, Jack had transformed. He had grown from a sickly 1.3-meter-tall boy into a 1.9-meter powerhouse. And he wasn't done growing. His appetite had become monstrous, he could eat enough in one sitting to feed a family for a week but every calorie was converted into pure, raw vitality. In the world of the Pirate King, a massive appetite was the clearest indicator of a person's potential for power.
Jack hoisted his heavy blade onto his shoulder and began the long walk out of the mountain pass. He moved with a relaxed, predatory grace.
As he walked, he practiced. SWISH. He sent another casual Flying Slash into the horizon, watching the blue light fade into the distance.
"If I keep this up," Jack muttered to himself, a smirk playing on his lips, "Between my Swordmaster status and the fact that I've started to awaken my Armament and Observation Haki... I should be able to hold my own, even in the first half of the Grand Line."
He wasn't interested in being a hero, and he didn't care about being the Pirate King. He just wanted to live without anyone's boot on his neck. He wanted to sail the seas, see the wonders of the world, and live a life of absolute freedom.
He tried to recall the timeline. Back on Earth, he had only watched up until the Dressrosa arc. He knew about the big players - Luffy, the Marines, the Four Emperors but the finer details were starting to blur after six years in this reality.
"Whatever," Jack said, shrugging off the uncertainty. "No point overthinking it now. I'll set sail when I'm ready. Whether it's the Straw Hats or the Admirals, if they get in my way, I'll just have to cut them down."
He looked at his calloused hands, feeling the immense power thrumming beneath his skin. With his "Heaven Rewards the Diligent" talent, he knew that reaching the pinnacle was no longer a question of if, but when.
"Even a commoner can stir up a storm if they work two hundred times harder than everyone else," Jack laughed, his voice echoing off the valley walls. "And I've got all the time in the world to grind."